G9MXE Furnace Installation Manual

The G9MXE is a high-efficiency gas furnace with variable-speed blower motor, multi-speed operation, and advanced diagnostic controls. This furnace features AFUE ratings up to 96%, two-stage gas valve operation, durable heat exchanger construction, integrated condensate management system, and compatibility with various thermostat configurations. Below are key sections for safety, specifications, installation procedures, wiring, startup, and troubleshooting.

Features at a Glance

Key components: Two-stage gas valve, variable-speed ECM blower motor, aluminized steel heat exchanger, integrated control board, pressure switches, flame sensor, and diagnostic LED.

Safety Precautions

Critical safety information for proper installation and operation.

1. Install furnace in accordance with all local codes and manufacturer specifications.
2. Ensure adequate combustion air and proper venting to prevent carbon monoxide hazards.
3. Verify gas type matches furnace rating plate (natural gas only).
4. Install carbon monoxide detectors in living spaces.
5. Keep combustible materials clear of furnace and vent pipes.

WARNING! Failure to follow safety precautions may result in fire, explosion, property damage, personal injury, or death. Gas furnaces must be installed by qualified technicians only.

Installation Requirements

Site preparation and clearance requirements.

1. Location: Indoor installation only, protected from weather and moisture.
2. Clearances: Minimum 1" from combustible materials, 6" from sides for service access.
3. Foundation: Level, solid surface capable of supporting furnace weight.
4. Ductwork: Properly sized and sealed return and supply ducts.
5. Electrical: 120V AC, 60Hz dedicated circuit with proper grounding.

CAUTION! Ensure installation location provides adequate service access and complies with local building codes.

Specifications

• Input Capacity: 60,000 - 120,000 BTU/H (model dependent)
• AFUE Rating: Up to 96%
• Gas Type: Natural Gas
• Gas Pressure: 3.5" WC natural gas inlet pressure
• Electrical: 120V AC, 60Hz, 15A circuit
• Blower Motor: Variable-speed ECM
• Stages: Two-stage heating operation
• Venting: PVC pipe (2" minimum diameter)
• Dimensions: Varies by model (check rating plate)
• Weight: 90-150 lbs depending on model

Installation Procedures

Step-by-step furnace installation.

1. Position furnace: Place on solid, level surface in approved location.
2. Connect ductwork: Attach supply and return ducts with proper sealing.
3. Install venting: Route PVC vent pipes according to local codes.
4. Connect gas supply: Use black iron pipe with proper thread sealant.
5. Wire electrical: Connect line voltage and thermostat wiring.
6. Install condensate drain: Route to approved drain location.
7. Verify installation: Check all connections and clearances.

WARNING! Furnace must be level for proper condensate drainage and operation.

Venting and Combustion Air

Proper vent system installation is critical for safe operation.

1. Use only PVC, CPVC, or ABS pipe approved for furnace venting.
2. Maintain minimum 1/4" per foot slope toward furnace for condensate drainage.
3. Install vent terminations according to local codes (typically 12" above ground/snow line).
4. Provide adequate combustion air per installation requirements.
5. Test vent system for leaks before operation.

Tip: Use primer and cement specifically designed for furnace vent pipe applications.

Electrical Wiring

Electrical connections and requirements.

1. Disconnect power before making electrical connections.
2. Connect 120V AC power to furnace junction box.
3. Wire thermostat: R, W, G, C, Y1, Y2 terminals as required.
4. Verify proper grounding of all electrical components.
5. Install disconnect switch within sight of furnace.

CAUTION! All electrical work must comply with National Electrical Code and local regulations.

Gas Supply Connection

Gas line installation and leak testing.

1. Use black iron pipe with proper size for BTU input.
2. Apply pipe thread sealant suitable for natural gas.
3. Install manual shutoff valve within 6 feet of furnace.
4. Connect flexible gas connector if local codes permit.
5. Pressure test gas line at 14" WC for 10 minutes (no drop).

WARNING! Never use an open flame to check for gas leaks. Use approved leak detection solution.

Startup and Commissioning

Initial startup procedure and system verification.

1. Verify all installation steps are complete and proper.
2. Open gas supply valve and check for leaks.
3. Restore electrical power to furnace.
4. Set thermostat to call for heat and observe ignition sequence.
5. Measure gas pressure and adjust if necessary.
6. Check temperature rise across heat exchanger.
7. Verify proper vent operation and condensate drainage.
8. Program thermostat for two-stage operation if applicable.

WARNING! Complete combustion analysis required for proper commissioning and safety.

Control Settings

Configuration options and control board settings.

DIP Switch Settings: Blower speeds, heating stages, accessory configuration.

Diagnostic LED: Flash codes for normal operation and fault conditions.

Thermostat Configuration: Compatible with single-stage and two-stage thermostats.

Blower Speeds: Configurable for various static pressure requirements.

Accessory Integration: Humidifier, electronic air cleaner, UV light compatibility.

Troubleshooting

Reset: Power cycle furnace to clear temporary fault conditions.

Service: Contact qualified HVAC technician for complex diagnostics and repairs.